This invention relates to an improved tubular net for food products, and in particular relates to an improved stitch for tubular net or netting.
The present invention may find many applications, and these applications may not be limited to the food industry. However, for easy description, the invention will be described in relation to its application for use in the food industry.
In the following description, the terms "casing", "food product" and "netting" shall have the following meanings:
______________________________________ "casing" any synthetic or natural tubular material used in the processing of food products such as meat products, "food product" any fresh or processed food products, and in particular fresh or processed meat products, and "netting" any knitted, woven, extruded or otherwise manufactured packaging netting which is elasticated, rigid or laterally extendible. ______________________________________
In the manufacture of food products, and in particular in respect of the manufacture of meat products, natural or artificial casings in the form of elongated tubes are normally either pumped full of meat from a machine specifically designed for the purpose, or have portions of meat placed within the tube prior to either a cooking or a curing process taking place.
In some cases, machines dealing with minced meat products use a feed mechanism for injecting meat through a delivery tube or injection horn where the casing is shirred onto the external surface of the delivery tube. A clip or other closure means is placed over the end of the casing, and a quantity of meat is then injected into the casing. Depending on the desired length of the meat product, the process is interrupted at various stages so that clips or twists may be applied to form separate and individual meat product portions.
In addition, whole meat portions may be inserted within tubular casing and, in this instance, stuffing tubes or horns are also used which enable the tubular casing to be stretched, whereupon meat portions can be readily introduced within the tubular casing.
In some cases, artificial skins such as collagen-based casings or fibrous casings have a tubular net or netting placed over the outside of the collagen once the food product is located within the casing. Alternatively, the food product may be inserted directly within the netting without the use of any inner casing.
In many instances, the netting is used primarily for decorative effect and remains in place prior to consumption of the food product. However, in addition to providing a decorative effect, the netting, if properly sized, can be used to produce a surface pattern effect. In this instance, the longitudinal and circumferential members of the net apply a force to the surface of the meat product and, provided that the surface of the food product is sufficiently resilient, then the netting will protrude into the surface of the food product. This results in a quilt-like surface pattern, where the circumferential and longitudinal members press into the surface of the food product so that the food product bulges outwardly within the square or rectangle formed by the longitudinal and circumferential members.
In addition to the appearance, it is also desirable, particularly in relation to the cooking or curing process, to maintain a desirable shape, and to apply constant compressive force to the meat product during the cooking or curing process. The constant pressure ensures that air pockets do not readily form within the meat, as this may lead to spoilage. It is also desirable to ensure that, particularly during a process where the meat product is hung to cure, no elongation or stretching of the meat product occurs.
In some instances, during a curing process, the weight of the meat product can cause the netting to stretch, thus resulting in a conical or tapered section from the hanging point to the beginning of the meat product. In many instances, depending on the type of the meat product, a small conical section of meat can be formed at the upper end. This particular section tends to be unsightly when the netting is removed, and is normally cut away and wasted.
This problem results from the fact that elastic netting is normally non-elastic in the longitudinal direction. Only the circumferential members, which form a continuous spiral, are normally formed from elastic material. The longitudinal members are formed from conventional chain stitching. Apart from the normal stretch which results from the knitting process, the netting is generally inextensible in the longitudinal direction. Accordingly, as there is no longitudinal elasticity, stretching and thinning at the upper end of the netting will occur during the curing process.